ABSTRACT:A new method of preparation of living cationic polymer of isobutyl vinyl ether via photoinduced polymerization in the presence of diphenyliodonium iodide (DPII, initiator) and zinc iodide in a mixed solvent of toluene/diethyl ether, which was irradiated at Ϫ78°C for short period, was completed within 15 min. The reaction was allowed for further reaction in the dark until monomer was fully consumed. It was found that increase in the conversion of monomer to polymer during the irradiation is very limited. Confirmation of the linear dependence of numberaverage molar mass of resulting polymer on % conversion together with the fact that polymerization proceeds until monomer consumption, and controllability of number-average molar mass of resulting polymer, depending on the molar ratio of monomer and initiator, strongly suggests the living nature of this polymerization, unless reaction temperature becomes higher than 0°C, i.e., the absence of chain breaking process. The narrow molar mass distribution, whose polydispersity index values are less than 1.2, reveals that the rate of initiation where irradiation is usually completed within 15 min is much faster than that of propagation in cationic nature in this system. Effect of some major factors, such as solvent polarity and temperature, on the living nature of the polymerization was also investigated.

Poly(vinyl alcohol) (PVA) having a number-average degree of polymerization of 7000 was obtained from the poly(vinyl acetate) (PVAc) having a number-average degree of polymerization 9000, a product of photo-induced emulsion polymerization of vinyl acetate (VAc), carried out at 0°C, using poly(oxyethylene) 10 nonyl phenyl ether ammonium sulfate as an anionic emulsifier. It was found that 100% conversion is always attained in the whole range of the investigation and the emulsifier plays an important role in the initiation process. The applicability of the photo-induced emulsion polymerization system to a relatively large-scale production was tested by using an apparatus equipped with an internal high-pressure Hg lamp with a capacity of several hundred grams per batch under nitrogen atmosphere. It was found that both the rate of polymerization and the degree of polymerization of resulting polymers are slightly lower than those obtained from corresponding small-scale polymerizations prepared on a high vacuum system because of the presence of oxygen.